Monomeric and oligomeric polyglycidyl ethers of substituted or unsubstituted tri(hydroxyphenyl) alkanes form a well defined class of epoxy resins which are known to have good high temperature properties. A thorough description of such resins and a method of synthesizing such resins is found in U.S. Pat. No. 4,394,496, inventor Paul G. Schrader, issued July 19, 1983. The resulting products are known to have outstanding heat distortion temperature and heat resistance when cured. Such is manifested by markedly increased service life at elevated temperatures, as well as other superior properties.
Epoxy novolac resins, including phenol formaldehyde novolac resins and cresol formaldehyde resins, are known to exhibit, in the cured state, reasonably high distortion temperatures and heat resistance although not as outstanding as those properties of the aforementioned polyglycidyl ethers of substituted or unsubstituted tri(hydroxyphenyl) alkanes.
It would be desirable if each of the types of epoxy resins discussed above had somewhat lower viscosity in the uncured state and greater tack without deleterious effect upon their known relatively high heat distortion and heat resistance performances when cured.